德尔福 - 拖动 &使用 ListView 拖放 [英] Delphi - Drag & Drop with ListView

问题描述

晚上好 :-)！

我有这段代码可以使用 Drag &文件的删除方法:

I have this code to use Drag & Drop method for files:

TForm1 = class(TForm)
...
public
    procedure DropFiles(var msg: TMessage ); message WM_DROPFILES;
end;

procedure TForm1.FormCreate(Sender: TObject)
begin
    DragAcceptFiles(ListView1.Handle, True);
end;

<小时>

procedure TForm1.DropFiles(var msg: TMessage );
var
  i, count  : integer;
  dropFileName : array [0..511] of Char;
  MAXFILENAME: integer;
begin
  MAXFILENAME := 511;
  count := DragQueryFile(msg.WParam, $FFFFFFFF, dropFileName, MAXFILENAME);
  for i := 0 to count - 1 do
  begin
    DragQueryFile(msg.WParam, i, dropFileName, MAXFILENAME);
    Memo1.Lines.Add(dropFileName);
  end;
  DragFinish(msg.WParam);
end;

<小时>

ListView 区域中是DragCursor，但在Memo1 中没有 任何记录.当我使用例如 ListBox 和方法 DragAcceptFiles(ListBox1.Handle, True) 时，一切都很好.

---

In area of ListView is DragCursor, but in Memo1 aren't any records. When I use for example ListBox and method DragAcceptFiles(ListBox1.Handle, True) ever is fine.

ListView 属性 DragMode 我设置为 dmAutomatic.

ListView property DragMode I set to dmAutomatic.

谢谢:-)

推荐答案

您已经为 ListView 调用了 DragAcceptFiles，因此 Windows 将 WM_DROPFILES 发送到您的 ListView 而不是您的 Form.您必须从 ListView 中捕获 WM_DROPFILES 消息.

You've called DragAcceptFiles for the ListView, so Windows sends the WM_DROPFILES to your ListView and not to your Form. You have to catch the WM_DROPFILES message from the ListView.

  private
    FOrgListViewWndProc: TWndMethod;
    procedure ListViewWndProc(var Msg: TMessage);
  // ...
  end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  // Redirect the ListView's WindowProc to ListViewWndProc
  FOrgListViewWndProc := ListView1.WindowProc;
  ListView1.WindowProc := ListViewWndProc;

  DragAcceptFiles(ListView1.Handle, True);
end;

procedure TForm1.ListViewWndProc(var Msg: TMessage);
begin
  // Catch the WM_DROPFILES message, and call the original ListView WindowProc 
  // for all other messages.
  case Msg.Msg of
    WM_DROPFILES:
      DropFiles(Msg);
  else
    if Assigned(FOrgListViewWndProc) then
      FOrgListViewWndProc(Msg);
  end;
end;

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